Increasing atmospheric CO₂ concentrations affect the performances of herbivores. Most previous studies have focused on the effects of abrupt increases in CO₂ concentration on herbivore performance, but knowledge about the response of herbivores to gradual increases in CO₂ is lacking. We tested the hypothesis that herbivores will show different responses to abrupt and gradual CO₂ increases. We measured the performance of the brown planthopper (BPH) (Nilaparvata lugens (Stål)) reared on rice for 15 successive generations under three CO₂ levels: ambient CO₂ (375 µl/L), a gradual increase in CO₂ (25 µl/L increase per generation, 390–750 µl/L), and an abrupt increase in CO₂ (750 µl/L). During the first generation, the female and male longevities were affected by both the gradual and abrupt increases in CO₂, and the fecundity and net reproductive rate (R₀) of the BPH in the abruptly increased CO₂ treatment were significantly lower than those in the other two treatments; there were no significant differences in the intrinsic rate of increase (r) and the finite rate of increase (λ) among the three CO₂ treatments. After 14 generations, female longevity was significantly prolonged in treatments with both gradual and abrupt CO₂ increases. The fecundity of the BPHs reared in the gradual CO₂ treatment was significantly higher than that in the other two CO₂ treatments. According to the population parameters (r, λ, and R₀) and population projection, under a gradual increase in CO₂, the BPH population size was higher than that under an abrupt CO₂ increase. We concluded that the BPH abundance will increase under a gradual CO₂ increase and consequently result in an increase in rice yield loss.

中文翻译：

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褐飞虱Nilaparvata lugens（Stål）对大气CO 2逐渐增加和突然增加的适应性

大气中CO ₂浓度的增加会影响草食动物的性能。以前的大多数研究都集中在CO ₂浓度突然增加对草食动物性能的影响上，但缺乏有关草食动物对CO ₂逐渐增加的反应的知识。我们检验了草食动物对CO ₂突然和逐渐增加的反应不同的假设。我们测量了在三个CO ₂水平下连续15代在水稻上饲养的褐飞虱（BPH）（Nilaparvata lugens（Stål））的性能，其中三个CO ₂水平为：环境CO ₂（375 µl / L），CO ₂逐渐增加（每代增加25 µl / L，390-750 µl / L），CO ₂突然增加（750 µl / L）。在第一代中，女性的寿命和男性的寿命都受到CO ₂的逐渐增加和突然增加的影响，而突然增加的CO ₂处理中BPH的繁殖力和净生殖率（R ₀）明显低于CO ₂。其他两种治疗；三种CO ₂处理之间的内在增长率（r）和有限增长率（λ）没有显着差异。经过14代后，逐渐和突然的CO ₂治疗均显着延长了女性的寿命增加。在渐进的CO ₂处理中饲养的BPH的繁殖力显着高于其他两种CO ₂处理。根据总体参数（[R ，λ，和- [R ₀）和人口投影，下CO的逐渐增加₂，在BPH种群规模下的突然CO高于₂的增加。我们得出的结论是，随着CO ₂的逐渐增加，BPH的丰度将增加，因此导致水稻产量损失的增加。